Journal of Computer Security - Volume 17, issue 2

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ISSN 0926-227X (P)
ISSN 1875-8924 (E)

The Journal of Computer Security presents research and development results of lasting significance in the theory, design, implementation, analysis, and application of secure computer systems. It also provides a forum for ideas about the meaning and implications of security and privacy, particularly those with important consequences for the technical community.

The journal provides an opportunity to publish articles of greater depth and length than is possible in the proceedings of various existing conferences, while addressing an audience of researchers in computer security who can be assumed to have a more specialized background than the readership of other archival publications. The journal welcomes contributions on all aspects of computer security: confidentiality, integrity, and assurance of service - that is, protection against unauthorized disclosure or modification of sensitive information, or denial of service. Of interest is a precise understanding of security policies through modelling, as well as the design and analysis of mechanisms for enforcing them, and the architectural principles of software and hardware systems implementing them.

Abstract: Public key infrastructure provides a promising foundation for verifying the authenticity of communicating parties and transferring trust over the Internet. The key issue in public key infrastructure is how to process certificate revocations. Previous research in this area has concentrated on the tradeoffs that can be made among different revocation options. No rigorous efforts have been made to understand the probability distribution of certificate revocation requests based on real empirical data. In this study, we first collect real data from VeriSign and suggest a functional form for the probability density function of certificate revocation requests. Exponential distribution function is…chosen as it adequately approximates the real data. We then provide an economic model based on which a certificate authority can choose the optimal Certificate Revocation List (CRL) release interval considering the intrinsic properties among different types of certificate services. To conclude we draw some insights by comparing the performance of four different CRL strategies.
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Abstract: Cryptographic schemes are often designed as a combination of multiple component cryptographic modules. Such a combiner design is robust for a (security) specification if it meets the specification, provided that a sufficient subset of the components meet their specifications. A folklore combiner for encryption is cascade, i.e. E e ″ ″ ( E e ′ ′ ( m ) ) . We show that cascade is a robust combiner for cryptosystems, under three important indistinguishability specifications: chosen plaintext attack (IND-CPA), non-adaptive chosen ciphertext attack…(IND-CCA1), and replayable chosen ciphertext attack (IND-rCCA). We also show that cascade is not robust for the important specifications adaptive CCA (IND-CCA2) and generalized CCA (IND-gCCA). The IND-rCCA and IND-gCCA specifications are closely related, and this is an interesting difference between them. All specifications are defined within. We also analyze few other basic and folklore combiners. In particular, we show that the following are robust combiners: the parallel combiner f ( x ) = f ″ ( x ) ‖ f ′ ( x ) for one-way functions, the XOR-input combiner c = ( E e ″ ″ ( m ⊕ r ) , E e ′ ′ ( r ) ) for cryptosystems, and the copy combiner f k ″ , k ′ ( m ) = f k ″ ″ ( m ) ‖ f k ′ ′ ( m ) for integrity tasks such as Message Authentication Codes (MAC) and signature schemes. Cascade is also robust for the hiding property of commitment schemes, and the copy combiner is robust for the binding property, but neither is a robust combiner for both properties. We present (new) robust combiners for commitment schemes; these new combiners can be viewed as a composition of the cascade and the copy combiners. Our combiners are simple, efficient and practical.
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Abstract: Storage-area networks are a popular and efficient way of building large storage systems both in an enterprise environment and for multi-domain storage service providers. In both environments the network and the storage has to be configured to ensure that the data is maintained securely and can be delivered efficiently. In this paper, we describe a model of mandatory security for SAN services that incorporates the notion of risk as a measure of the robustness of the SAN's configuration and that formally defines a vulnerability common in systems with mandatory security, i.e. cascaded threats. Our abstract SAN model is flexible enough…to reflect the data requirements, tractable for the administrator, and can be implemented as part of an automatic configuration system. The implementation is given as part of a prototype written in OPL.
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Abstract: Because of its ease of administration, role-based access control (RBAC) has become the norm to enforcing security in most of today's organizations. For implementing RBAC, it is important to devise a complete and correct set of roles. This task, known as role engineering, has been identified as one of the costliest components in deploying RBAC. A key problem with respect to role engineering is that there is no formal metric for measuring the goodness/interestingness of the devised set of roles. Recently, Vaidya et al. [26], formally define the role mining problem (RMP) as the problem of discovering an optimal set…of roles from existing user permissions, and analyze its theoretical bounds. Essentially, given a user-permission assignment (UPA), the basic RMP is to discover the user-role assignment relation (UA) and role-permission assignment relation (PA) such that the number of roles required is minimum. In this paper, we present another interesting and useful problem, called the edge-RMP, with a different minimality objective. The edge-RMP, requires the discovery of a complete and correct set of roles such that the discovered |UA|+|PA| is the minimum possible. Minimal |UA|+|PA| is a useful metric as it would minimize the administrative burden since less number of assignments need to be managed. Although the basic-RMP and the edge-RMP appear to be related problems, we demonstrate with concrete examples that they are, in fact, independent of each other. We prove that the edge-RMP is an NP-hard problem by reducing the known “vertex cover problem” to the decision version of the edge-RMP. Another important contribution of this paper is to provide a binary integer programming solution to this problem by showing that the edge-RMP can be formulated in that form. As a result, one can directly borrow existing implementation solutions for binary integer programming and guide further research in this direction. We also propose a heuristic solution for large scale problems, and experimentally validate our algorithm.
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